This chapter examines ruin towns: civil defence training grounds that replicated urban war zones. The ruins provided a stage for enacting nuclear war, where the merely imagined was given a tangible expression. The chapter sketches the transnational extension-by-invitation of a British model of ruins to Denmark, and through architectural and historical analysis, it asks how it was re-embedded into a new national context and appropriated to local needs to become part of the common Danish civil defence landscape. The chapter, then, discusses how these ruin towns contributed to an affirmation of social norms and values, arguing that they caused a taming of the nuclear catastrophe as well as reflecting and reinforcing a specific political and historically situated understanding of social urban order and the good society.